EPA is making available two updated draft documents that provide technical assistance for states implementing the 2010 health-based, sulfur dioxide (SO₂) standard.  These documents provide technical advice on the use of modeling and monitoring to determine if an area meets the 2010 SO₂ air quality standard.

For more information see Sulfur Dioxide State Implementation Plan (SIP) Checklist Guide.

• Sulfur Dioxide (SO2) National Ambient Air Quality Standards Designations Modeling Technical Assistance Document (August 2016 DRAFT) (pdf) (1.4 MB)
• Source-Oriented Sulfur Dioxide (SO2) Monitoring Technical Assistance Document (February 2016 Draft) (pdf) (3.16 MB)